Internet Small Computer System Interface (iSCSI) is an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. The iSCSI protocol can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval. The protocol allows clients (called initiators) to send SCSI commands via Command Descriptor Blocks (CDBs) to SCSI storage devices (targets) on remote servers. The iSCSI protocol is a storage area network (SAN) protocol that is a block storage protocol, allowing organizations to consolidate storage into data center storage arrays while providing hosts (such as database and web servers) with the illusion of locally attached disks.
The Data Center Bridging Exchange (DCBX) standard defined by IEEE describes a method for bandwidth allocation that can be implemented on an iSCSI network link. However, even with the DCBX protocol implemented, the availability of resources on a server may not be visible to a Guest Partition from a client point-of-view.
Furthermore, a unified quality of service (QoS) between the Guest Partition and the server resource is not guaranteed in a configuration implementing the DCBX protocol alone. For example, the client side of a configuration can apply a QoS on its side of the network, but if the server does not guarantee the same QoS parameters, the configuration on the client side may have no effect from an end user perspective.
A logical unit may be a device addressed by a SCSI protocol or protocols which encapsulate SCSI. The SCSI protocol may be, for example, iSCSI. There are different methods of providing direct access to a Logical Unit from a Guest Partition. A software only implementation of an iSCSI Initiator can be run directly on a Guest Partition. However, this option is available only for a software implementation of an iSCSI Initiator.
An iSCSI Initiator running on a Hypervisor can log into the iSCSI target, and the Hypervisor can map the Logical Units to a Guest Partition in pass-through mode. However, using the pass-through mode may prevent the use of additional capabilities that exist in the hardware, therefore limiting the competitive benefit of this option.
A hardware implementation of an iSCSI Initiator can be virtualized by way of storage single root I/O virtualization (SR-IOV), and an iSCSI Login can be directly issued to a Guest Partition completely bypassing the Hypervisor. However, this option is dependent on Hypervisor vendors implementing Storage SR-IOV, which is not widely accepted.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present disclosure as set forth in the remainder of the present application with reference to the drawings.